Evaluation of Effects of Non-Vehicle Hazards Characteristics on Accident Likelihood in Rural Divided Roads

Transportation safety is the most important criterion in the engineering design of roads. Rural roads pedestrian accidents statistics show that this type of accident is tremendously important. From the safety point of view drivers need to have a reasonable time window for hazard recognition, reaction initiation and execution. This means that the hazard has to be in sight from a distance longer than the minimum stopping sight distance. Nevertheless, if the road side configuration make the sight available for a very long distance, it’s the hazards characteristics which defines the visibility along with the drivers’ behavioral characteristics as a human. The hazard color and mobility are some of the most important hazard characteristics. In this research using some variables of hazard characteristics, a linear accident probability model was developed and the effect of these characteristics and their interactions was investigated. The use of driving simulator was in order to prepare a ceteris paribus laboratory condition. Randomly invited, the test takers were 80 over 18-years-old person who had a driver license. The simulated environment was a straight rout in a plain terrain in which the driver’s sight were not obstructed. Drivers encountered averagely 14 hazards in this road including some pedestrian crossing the road with black or white out-fit and some black or white rocks in the road. The rocks were modeled to enable the comparison between the effects of state of being mobile or fixed on accident likelihood. According to the findings of this research, speed has an increasing effect and the number of prior facing with hazards had a decreasing effect on the accident likelihood, although this effect was not so considerable. The hazards including pedestrians and rocks with black color was about 26% more likely to be involved in an accident in night time in comparison with the white ones. This likelihood is estimated to be about 2% less in day time.